Is resting with Slim, naked - they may be in bed (6)
I believe the answer is:
lilies
'is resting' is the definition.
I can't judge whether this defines the answer.
'with slim naked they may be in bed' is the wordplay.
'with' is a charade indicator (letters next to each other).
'naked' says to take the centre (outside letters removed so centre is unclothed).
'they may be in bed' becomes 'lies' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The centre of 'slim' is 'li'.
'li'+'lies' is 'LILIES'.
Can you help me to learn more?
(Other definitions for lilies that I've seen before include "'Showy flowers, most have a strong smell (6)'" , "Plants with slender stems and large trumpet-shaped flowers" , "Luke: ` `Behold the ...... of the field' '" , "Flowers for when 'e is ill" , "'''Consider the ... of the field, how they grow'' (Bible) (6)'" .)